Hydrocarbons, such as oil and gas, are commonly obtained from subterranean formations that may be located onshore or offshore. The development of subterranean operations and processes involved in removing hydrocarbons from a subterranean formation are complex. Typically, subterranean operations involve a number of different steps such as, for example, drilling a wellbore through and/or into the subterranean formation at a desired well site, treating the wellbore to optimize production of hydrocarbons, and performing the necessary steps to produce and process the hydrocarbons from the subterranean formation. Some or all of these steps may require and utilize measurements and other sensed data to determine characteristics of the formation, the hydrocarbon, the equipment used in the operations, etc.
One example type of sensed data includes seismic data in the form of a Vertical Seismic Profile (VSP). VSP may refer to the measurement of seismic/acoustic energy in a wellbore originating from a seismic source at a surface of the wellbore (e.g., a vibrator truck, air gun, weight drop, and/or explosives). Traditionally, measurements using VSP (VSP data) are collected using a string of approximately equally spaced geophones and/or hydrophones that are lowered into a wellbore. VSP sampling of a seismic wave field using geophones or hydrophones is typically limited to resolutions on the order of tens of feet.
While the use of geophones or hydrophones enables collection of VSP data in three orthogonal directions, referred to as three-component (3-C) data, deployment of geophone strings for VSP is expensive and time consuming. For example, the geophone string needs to be inserted and retracted before and after each VSP data collection, which, in the case of a producing well, implies that production needs to be halted during collection.
An alternate method of VSP data collection may include the use of DAS techniques. In DAS VSP a fiber optic cable is deployed in the wellbore. Relative to VSP using geophones or hydrophones, DAS VSP provides simplified deployment that does not interfere with operations in the wellbore, acquisition of instantaneous measurement data along a length of the wellbore, and improved resolution. However, DAS VSP data is acquired as only a single component along an axial direction of the fiber optic cable, as opposed to traditional VSP data that can acquire 3-C data in multiple directions.
The ability to improve directionality of data obtained by seismic profiling is of direct relevance to hydrocarbons removal from subterranean formations, particularly for DAS VSP. Accordingly, there is continued interest in the development of improved DAS VSP that can acquire 3-C data.